You just get a dumb probe sensor, typically around $15. Foam insulate it on three sides and attach it with the other side touching the pipe. ( usually you attach the probe to the pipe first, then insulate over it. )
Connect it to a Z wave device That can read the temperature from the probe. There are a couple of options for this, Typically costing from $25-$65. That Gives you your smartthings integration and keeps the zwave radio away from the pipe and the insulation.
Discussion of Z wave options with probe sensors (this is a clickable link)
